China Focus: Chinese and French Researchers Complete Lunar Radon-Gas Detection Mission

Historical Context: The Chang’e lunar exploration program, named after the Chinese moon goddess, represents China’s ambitious efforts in space exploration. Initiated in 2004, the program has seen multiple successful missions, including Chang’e-3, which achieved the first soft landing on the moon since 1976, and Chang’e-4, which made the first-ever landing on the far side of the moon in 2019. The Chang’e-6 mission continues this legacy, marking a significant milestone in international collaboration in space research.

Article: BEIJING, July 3 (Xinhua) – A team of Chinese and French researchers has successfully completed a mission to measure the distribution of radon gas and polonium on the moon. This was achieved using the French payload aboard China’s Chang’e-6 lunar probe, as reported by the Institute of Geology and Geophysics (IGG) of the Chinese Academy of Sciences.

The French payload, named Detection of Outgassing RadoN (DORN), is designed to measure radon gas, its decay products on the lunar surface, and charged particles in the space environment. The scientific objectives include studying the origin and dynamics of the lunar atmosphere, the thermal and physical properties of lunar soil, and the movement of lunar surface dust.

He Huaiyu, co-chief scientist of the DORN from the IGG, noted that the payload equipment had been exposed to Earth’s atmosphere for several months before launch. It was first activated on May 6 during the lunar-orbit cruise period, approximately 320,000 kilometers from Earth, and operated for about 10 hours to measure background noise and natural pollution on the lunar surface. Following historic solar storms between May 10 and 11, the instrument was powered on again on May 17, performing measurements in lunar orbit for a total of 32 hours.

“The data beamed back to Earth confirmed that all 16 detectors of the radon-measurement instrument were functioning properly. The data obtained included the flux of charged particles in the solar wind and their decay over time, as well as the lunar shielding effect on these particle fluxes,” said Li Jiannan, Chinese technical head from the IGG.

The DORN was restarted on May 23 and conducted orbital measurements of radon and polonium distribution on the moon for 111 hours. On June 2, shortly after the Chang’e-6 lunar probe landed in the South Pole-Aitken Basin on the far side of the moon, the radon-gas detector began its surface measurements. On June 4, when the ascender of Chang’e-6 took off from the moon with samples, it completed its detection mission and became a “permanent resident” on the far side of the moon.

He Huaiyu highlighted that this collaboration marks the first between China and France in deep-space exploration, contributing to the mission’s success. China’s Chang’e-6 spacecraft, launched on May 3, carried four international payloads from the European Space Agency, France, Italy, and Pakistan. The upcoming Chang’e-7 mission will carry six international scientific instruments, and Chang’e-8 will offer 200 kilograms of international payload capacity, with over 30 applications already received, according to Liu Yunfeng, deputy director of the China National Space Administration’s international cooperation department.

Summary:

• Chinese and French researchers completed a lunar radon-gas detection mission using the Chang’e-6 lunar probe.
• The French payload, DORN, measured radon gas, its decay products, and charged particles in the lunar environment.
• The mission aimed to study the lunar atmosphere, soil properties, and surface dust movement.
• The payload was activated multiple times, including after historic solar storms, to gather comprehensive data.
• The collaboration marks the first deep-space exploration partnership between China and France.
• Chang’e-6 carried international payloads from the European Space Agency, France, Italy, and Pakistan.
• Future missions, Chang’e-7 and Chang’e-8, will continue to involve international scientific cooperation.